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Long Term Evolution: 4G is Here

Written by Jennifer Gavigan

Long Term Evolution (LTE) is a hot topic in public safety right now. LTE is the latest standard in mobile network technology. It is a project of the 3rd Generation Partnership Project (3GPP), operating under a name trademarked by one of the associations within the partnership, the European Telecommunications Standards Institute.

The current generation of mobile telecommunication networks is collectively known as 3G (for “third generation”). Although LTE is often marketed as 4G, first-release LTE is actually a 3.9G technology because it does not fully comply with the IMT Advanced 4G requirements. The pre-4G standard is a step toward LTE Advanced, a fourth generation standard (4G) of radio technologies designed to increase the capacity and speed of mobile telephone networks.

LTE Advanced is backward compatible with LTE and uses the same frequency bands, while LTE is not backward compatible with 3G systems. Just as 3G was an improvement over 2G, LTE is an improvement over 3G (more than 15 times faster).

The overall objective for LTE is to provide an extremely high performance radio-access technology that gives users the same capabilities in a mobile setting that they normally get only on fixed networks. In addition, it can readily coexist with HSPA and earlier networks. Because of scalable bandwidth, operators will be able to easily transfer their networks and users from HSPA to LTE over time.

What all of this means is LTE meets the mission-critical needs of first responders in the field by providing greater data sharing in both directions. This includes: high-definition video streaming; high-resolution photos; detailed maps and blueprints; Web, e-mail and text messaging; transfer of large files; access to remote databases; automatic vehicle location (AVL) and more—all faster than ever before. With LTE, volumes of data can be received in mere seconds.

LTE is endorsed by public safety organizations (APCO, NENA, etc.) in the United States as the preferred technology for the new 700 MHz public-safety radio band. Despite the growing market for regional LTE networks for first responders, there is still a logjam over how best to create a nationwide, interoperable public-safety broadband network using the D Block of the 700 MHz band. Public safety groups are pressing Congress to allocate the spectrum directly to first responders, while the FCC is still advocating a re-auction of the spectrum.

Still, advances are being made. Alcatel-Lucent completed the first data call using an LTE network operating on the 700 MHz spectrum reserved for public safety use in the United States. Alcatel-Lucent teamed with EADS Defence and Security/PlantCML to jointly develop a next-generation public-safety communications solution based on LTE and U.S. public safety standards. Motorola and Ericsson are also partnering to make communications a snap for public safety agencies via an LTE-based voice and data mobile broadband system.

Verizon Wireless and AT&T Mobility here in the States and several worldwide carriers announced plans, beginning in 2009, to convert their networks to LTE. Much of 3GPP Release 8 focuses on adopting 4G mobile communications technology, including an all-IP flat networking architecture. Both carriers said LTE provides a more natural upgrade for their GSM-based networks and subscribers—and GSM is the dominant mobile standard worldwide, with more than 3 billion global customers as of February 2010.

LTE is a modulation technique that is designed to deliver 100 Mbps per channel and give individual users performance comparable to today’s wired broadband. Continuity of operations, i.e., keeping the network up, is a critical part of public safety’s reliance on cell communication in emergency situations. The performance and capabilities of 4G LTE will be unmatched in the marketplace, allowing public safety personnel (as well as commercial users) to do things never before possible in a wireless environment.

Verizon Wireless

Verizon’s 4G Long-Term Evolution (4G LTE) network is set to launch in 38 U.S. markets this year. This ultra-fast wireless 4G LTE network gives first responders immediate access to important, large data files from the field (video, mapping and GPS applications, etc.). Some of the advantages that Verizon Wireless’ implementation of 4G LTE will provide include the following:

Higher data rates: With Verizon Wireless’ 10 + 10 MHz implementation, LTE will be supporting average data rates per user of 5-12 Mbps in the forward link, and 2-5 Mbps in the reverse link. Both maximum and average LTE data rates are significantly higher in the reverse and forward links than those supported by existing 3G networks. LTE will enable video application on the downlink as well as uplink, including, but not limited to, video sharing, surveillance, conferencing and streaming in higher definition than is possible with existing 3G technology today.

Better multipath, mobility and power performance: The advanced radio characteristics of LTE address several issues that have traditionally crippled cellular wireless, including multipath and multiuser interference. LTE’s use of Orthogonal Frequency-Division Multiple Access (OFDMA) and multiple-input and multiple-output (MIMO) in the downlink transmission effectively eliminates intra-cell multiuser interference and minimizes inter-cell multiuser interference, thereby maximizing performance.

Similarly, the single carrier frequency-division multiple access (SC-FDMA) uplink transmission allows for user equipment to transmit low power signals without the need for expensive power amplifiers. Improvement in battery power consumption in end-user devices (UEs) is a side benefit of the coverage and multipath/power performance advantages offered by LTE.

Latency: The user plane latency achieved in LTE is approximately one-fourth the corresponding latency in existing 3G technologies, providing a direct service advantage for highly immersive and interactive application environments, such as multiplayer gaming and rich multimedia communications.

Simultaneous user support: LTE provides the ability to perform two-dimensional resource scheduling (in time and frequency), allowing support of multiple users in a time slot, resulting in a much better always-on experience while enabling the proliferation of embedded wireless applications/systems. In contrast, existing 3G technology performs one-dimensional scheduling, which limits service to one user for each timeslot.

Verizon Wireless is the first company in the U.S.—and among the first in the world—to launch LTE with a sizeable footprint. Verizon commercially launched its 4G LTE network in 38 major metropolitan areas, covering more than 110 million Americans, at the end of 2010.

In addition, the company is launching 4G LTE in more than 60 commercial airports coast to coast—both the airports within the launch areas, plus airports in other key cities. In subsequent years, an equally aggressive growth plan will result in full nationwide coverage in 2013. Verizon’s 4G LTE network will ultimately connect a full range of electronics devices and machines to each other.

Verizon Wireless plans to utilize its nationwide, contiguous 700 MHz spectrum to deploy 4G LTE. This spectrum covers the entire lower 48 states and Hawaii and gives customers the nationwide bandwidth and coverage they need, when and where they need it. Verizon Wireless’ 4G LTE network will be backward-compatible with its existing 3G network.

That means the two networks will coexist, and services will be integrated between LTE and the 3G Evolution-Data Optimized (EV-DO) Rev A network. Verizon will also support handover to existing mobile networks, thereby providing seamless coverage to Verizon Wireless subscribers right from the start.

In order to provide access to the 4G LTE network to more of the U.S. population living in rural areas, Verizon Wireless plans to work with rural companies to collaboratively build and operate a 4G network in those areas using the tower and backhaul assets of the rural company and Verizon Wireless’ core LTE equipment and 700 MHz spectrum. Verizon Wireless provides a unique opportunity for selected participants to leverage the company’s technical and spectrum resources.

Motorola Solutions

The Motorola Solutions business of Motorola Inc. demonstrated live over-the-air (OTA) broadband video in the 700 MHz public safety spectrum band to the world’s first public safety data device using a commercial LTE chipset module in November.

The LTE module used in the demonstration at the 2010 Motorola Digital Users Group Conference is ready for implementation in a broad array of public safety LTE devices in multiple form factors. The compact USB device uses a commercially produced chipset that supports the Band Class 14 public safety spectrum band. The demonstration is a key milestone in the development of open market components to foster a broad selection of LTE devices that are optimized for use by public safety and benefit from economies of scale from carrier LTE deployments worldwide.

The portfolio of LTE devices will include portable data adaptors, vehicular modems and multimedia handhelds, among others. Motorola is making additional investments to fully enhance standards-compliant LTE components to serve the unique requirements of public safety operations. Motorola’s LTE technology demonstration includes dynamic prioritization and preemption for safeguarding LTE capacity for critical resources during an emergency response. Motorola has also developed real-time video intelligence that adjusts video to best match real-time wireless LTE bandwidth capabilities with the device screen size.

Motorola congratulated BayWEB for its first live OTA data session in the San Francisco Bay Area. This live data session marks the first operational use of the public safety broadband spectrum in a true public safety deployment. “We are committed to bringing LTE broadband services to the Bay Area. This first video session is a major step in making this system a reality to provide broadband for public safety,” said Undersheriff Rich Lucia, Alameda County.

“Motorola continues to make technology breakthroughs in the development of communications solutions for public safety. The demonstration of the first 700 MHz public safety broadband-ready module is a testament to our focus on bringing public safety-optimized devices that will provide the advanced communications tools public safety personnel need for officer safety and to serve their communities,” said Darren McQueen, corporate vice president, Private Broadband, Motorola Solutions.

Ultimately, LTE is a giant step forward for public safety because of its unprecedented broadband capabilities. Today’s first responders need interoperability to perform their jobs efficiently and safely. LTE is a technology that companies as well as public safety agencies need to embrace in order to communicate without interruption or interference. Jennifer Gavigan is the editor of Public Safety IT. She can be reached at jgavigan@hendonpub.com.